Bi-annual US dollars 1987-06-30 69 1987-12-31 79 1988-06-30 39 1988-12-31 56 1989-06-30 22 1989-12-31 34 1990-06-30 19 1990-12-31 83 1991-06-30 73 1991-12-31 0 1992-06-30 19 1992-12-31 79 1993-06-30 99 1993-12-31 22 1994-06-30 20 1994-12-31 183 1995-06-30 92 1995-12-31 54 1996-06-30 9 1996-12-31 50 1997-06-30 78 1997-12-31 7 1998-06-30 100 1998-12-31 200 1999-06-30 136